Trees taken down to fight invasive insects at Bear Brook

At the end of a mud road by the Allenstown entrance at Bear Brook State Park sits heavy equipment and a sprawling and towering stack of cut trees.

Track-scarred earth, brush and branches litter the ground. At first, it might seem to be a significant logging operation in the middle of a state park.

But, what isn't immediately clear is that all of this activity is to protect New Hampshire's forests from a far more devastating, though nearly microscopic force: the red pine scale.

Red pine scales are an invasive insect that feast on red pine trees until the host dies after three to five years. They're a particularly nasty kind of infestation, being resistant to pesticides and without natural predators in New England, leaving their spread - largely through the wind, birds, and squirrels - unchecked and rapid once they've taken hold. Infestations in Connecticut and Rhode Island have virtually wiped out the red pine populations in those states, and have wreaked havoc in Massachusetts.

The Bear Brook infestation, discovered in August of 2012 and covering 120 acres of forest, is the insect's first appearance in New Hampshire, but forestry officials are taking action in the hope that that they can stop the invasion from spreading beyond the park gates, where it seems to be confined for the moment.

The only effective response, however, is to kill the host. That process began on Feb. 20, and the park visibly bares the scars.

"This isn't how we like to manage our parks. . It's a last resort," said Chief of Forest Management for the New Hampshire Forest Protection Bureau, Ken Desmarais.

"[But] if we didn't cut these stands, we would just have 120 acres of standing dead trees, and at that point we wouldn't be able to sell them, and we wouldn't have the manpower to cut them, and it would be too dangerous for people to recreate under them because they'd be falling down all the time."

Whether this will ultimately stop the spread, however, is uncertain. Massachusetts took a similar course upon discovering their infestation to no avail.

The bureau has yet to decide whether red pines will be reintroduced into the park. For the moment, because the trees don't naturally grow in the "pure stand" environment in which they were planted, the bureau is considering letting the forest repopulate itself naturally.

In the meantime, however, the forest will not be completely barren. Stands of young white pines, described by forest officials as "the next generation" of the forest, are growing nearby.

Red pine trees, which are native to the upper Great Lakes region, were introduced to the state park in the 1930s, as they were in many states in New England, when they were planted by the Civilian Conservation Corps, a workforce program under Franklin Roosevelt. Money was also raised by the Daughters of the American Revolution to plant and manage the red pine stands.

Why the parasites are showing up this far north now isn't clear. Desmarais theorized that they were able to make a foothold in the state because of the relatively warm winters in recent years. Red pine scales first appeared in North America in 1946, with the earliest reports being in Connecticut. According to the forest protection bureau, it's likely that they were introduced to North America at the 1939 New York World's Fair, where a number of exotic trees were imported for display. By the 1960s, the scales were found in New York, New Jersey, and Rhode Island.